Be careful with Sony music players. Until very recently, the only format the players supported was Sony's own ATRAC format. While they advertised MP3 compatibility, they made you convert the MP3 files to ATRAC. As both are lossless, the quality dropped during conversion, as well as leaving you with two copies of everything.
Some of Sony's new players do support MP3 files natively, you just have to watch out.
goates